LASER GLASS HOST COMPOSITIONS COMPRISING TeO{11 , Li{11 O AND ZnO

ABSTRACT

Laser glass host compositions for effective lasing amounts of Nd2O3 are disclosed, the host compositions comprising TeO2, Li2O and ZnO in certain molar amounts. Also disclosed are methods of making highly effective laser articles, such as rods, and also the new use of the above-described glass compositions for forming laser articles, the new use including forming laser articles from the compositions, pumping the resultant laser articles to provide an energy inversion, and lasing the pumped articles.

llnited States Patent Cooley Sept. 17, 1974 LASER GLASS HOST COMPOSITIONS COMPRlSlNG 0,, Li 0 AND ZnO lnventor: Richard F. Cooley, Toledo, Ohio Assignee: Owens-Illinois, Inc., Toledo, Ohio Filed: June 27, 1973 Appl. No.: 374,108

U.S. Cl. 331/9415, 252/3014 Int. Cl. H015 3/16 Field of Search 331/945; 252/301.4, 301.6;

References Cited UNITED STATES PATENTS 8/1969 Pearson et al. 331/945 Primary ExaminerWilliam L. Sikes Attorney, Agent, or Firm-Richard D. Heberling; E. J. Holler [5 7] ABSTRACT Laser glass host compositions for effective lasing amounts of Nd O are disclosed, the host compositions comprising TeO Li O and ZnO in certain molar amounts. Also disclosed are methods of making highly effective laser articles, such as rods, and also the new use of the above-described glass compositions for forming laser articles, the new use including forming laser articles from the compositions, pumping the resultant laser articles to provide an energy inversion, and lasing the pumped articles,

14 Claims, 1 Drawing Figure LASER GLASS HOST COMPOSITIONS M RISING T 1 29 A Z PS INVENTION The present invention relates to laser glass host compositions for effective lasing amounts of Nd O the host compositions comprising TeO U and ZnO. The present invention also relates to methods of making laser articles, such as laser rods, the methods in cluding the steps of:

l. melting laser glass batch-forming materials to provide a glass composition comprising certain amounts of TeO Li O and ZnO, the glass compositions being a host for an effective lasing amount Of 2. forming a glass laser blank from the molten glass;

and

3. fabricating a laser article from the blank to provide a very efficient laser article.

The present invention also relates to the new use for TeO /Li O/ZnO glass compositions for making glass laser articles, in which the composition contains an effective amount of Nd O the new use including the steps of:

1. forming laser articles from glass compositions comprising TeO U 0 and ZnO, the glass composition being a host for Nd O 2. pumping the laser article to provide an energy inversion; and

3. lasing the pumped article.

The present invention also relates to outstanding glass laser articles, such as rods and discs, which are made from glass host compositions TeO Li O and ZnO.

It is desirable to provide laser glass compositions that can be used to make outstanding, highly efficient glass laser articles. It is desirable also to provide methods of making the articles and to provide the new use for glass compositions comprising TeO Li O and ZnO in which the new use includes the steps of:

1. forming a glass laser article from the above described glass composition that is a host for an effective lasing amount of Nd O 2. pumping the laser article; and thereafter 3. lasing the pumped article.

It is an object of the present invention to provide a glass laser composition containing TeO U 0 and ZnO in which the molar proportions of TeO Li O and ZnO are defined in a general range by the area within the heavy lines connecting the points ABCDEF in the ternary diagram of the FIGURE of the drawings, the glass composition also being a host for an effective lasing amount of Nd O It is an object of the present invention to provide a method for making a glass article, such as a laser rod, disc or the like, in which the method comprises the steps of:

l. melting laser glass batch-forming materials to provide a molten glass comprising TeO U 0 and ZnO in which the molar proportions thereof are defined by the area within the heavy lines connecting the points ABCDEF of the ternary diagram of the FIGURE, the glass also being a host for Nd O 2. forming a glass laser blank from the molten glass;

and

3. fabricating a laser article from the blank to provide a very efficient laser article.

It is an object of the present invention to provide the new use for a glass composition for making a glass laser article thereof in which the glass comprises TeO U 0 and Zn() in which the molar proportions thereof are defined in a general range by the area within the heavy lines connecting the points ABCDEF of the ternary diagram of the FIGURE, and in which the glass composition is a host for an effective lasing amount of Nd O the new use comprising the steps of:

1. forming a glass laser article from the glass composition comprising TeO U 0 and ZnO along with an effective lasing amount of Nd O 2. pumping the laser article to provide an energy inversion; and

3. lasing the pumped laser article.

It is an object of the present invention to provide an efficient glass laser article, such as a rod or disc, made from a glass composition comprising TeO U 0 and ZnO, the glass composition containing Nd O These and other objects will become apparent from the specification that follows, the appended claims, and the drawings, in which the FIGURE is a ternary diagram of the glass host composition of the present invention in which the molar proportions of TeO Li O and ZnO are defined by the area within the heavy lines of the ternary diagram.

The present invention provides outstanding laser glass host compositions for effective lasing amounts of Nd O the host compositions comprising TeO U 0 and ZnO in certain molar amounts that are defined generally by the area within the heavy lines connecting the points ABCDEF of the ternary diagram of the FIG- URE of the drawings. Preferably, the molar amounts of TeO U 0 and ZnO are defined by the area within the heavy lines connecting the points Gl-IIJKL in the ternary diagram.

The present invention also provides methods for making highly efficient glass laser articles, such as rods or discs, the methods comprising the steps of:

1. melting laser glass batch-forming materials to provide a molten glass comprising TeO U 0 and ZnO in which the molar amounts thereof are defined in a general range by the area within the heavy lines connecting the points ABCDEF of the ternary diagram, the molten glass being a host for an effective lasing amount of Nd O 2. forming a glass laser blank from the molten glass;

and

3. fabricating the outstanding laser article from the blank.

The present invention also provides the new use for a glass composition as a glass laser article in which the glass comprises TeO U 0 and ZnO in which the molar proportions thereof are defined in a general range within the area formed by the heavy lines connecting points ABCDEF of the ternary diagram, the glass being a host for an effective lasing amount of Nd O the new use comprising the steps of:

1. forming a glass laser article from the glass composition;

2. pumping the laser article to provide an energy inversion; and

3. lasing the pumped laser article.

A zinc tellurite glass consisting essentially of a major molar proportion of TeO and between about 20 and 40 molar percent of ZnO is described and claimed in the Redman U. S. Pat. No. 3,423,326. These zinc tellurite glasses were reported as having some fluorescent activity when doped with Nd O As previously indicated, the outstanding laser glass host compositions of the present invention exhibit much higher fluorescent activity than the zinc tellurite glasses of the Redman patent, the increased fluorescent activity indicating a greater lasing efficiency for laser articles made from the host compositions of the present invention. As previously described, only certain molar proportions of TeO U and ZnO can be used to provide the highly efficient laser articles.

The increase in fluorescent activity, when compared to the host glasses of the Redman patent, is generally at least about 50 percent and preferably around 60 or 70 percent, the increase being at least 50 percent when compared to the working examples of the Redman patent.

The above glass laser composition is set forth in U.S. Pat. No. 3,471,409 to Lee and Rapp.

Generally, the highest fluorescent intensity value for a zinc tellurite glass as above-described containing 35 mole percent ZnO, is about 2.09, and the highest fluorescent intensity value of the above-described lithiacalcia-alumino silicate glass laser, which is the reference laser glass, is held to be 1.0.

The following examples are intended to illustrate the present invention and not to limit the same in any way.

EXAMPLE 1 PART A A gram melt was prepared by mixing reagent grade raw materials, in the following molar percent and also for convenience, weight percent, with ml. of l l-n Ingredients Mole Percent Weight Percent TeO,

ZnO

Li O

Nd O

There is no mention of any glass system other than that ofa glass host composition consisting essentially of tellurium oxide and zinc oxide in the Redman patent. There is no suggestion in the Tedman patent that such highly efficient laser articles can be made from a laser glass host composition containing only certain molar proportions of TeO U 0 and ZnO.

The outstanding laser glass host compositions of the present invention generally contain about 60-85 mole percent TeO about 2-20 mole percent U 0 and about 5-35 mole percent ZnO. As previously indicated, a host glass contains an effective lasing amount of Nd O which is generally about 0.01-l.5 mole percent and preferably about 0.5-1.2 percent.

Preferred compositions are those in which the glass host comprises about 79-81 mole percent TeO about 4-6 mole percent U 0 and about 14-16 mole percent ZnO. Specific glass compositions that provide excellent results are those, for example, in which the host glass comprises about 80 mole percent TeO about 6 mole percent Li O and about 14 mole percent ZnO; or a glass that comprises about 79 mole percent TeO about 6 mole percent U 0 and about 15 mole percent ZnO.

In accordance with the present invention, the increase in fluorescent activity for the laser glass articles of the present invention is surprisingly at least about 50 percent over that of a zinc tellurite glass containing 65 mole percent TeO- and mole percent ZnO and at least percent over that ofa lithia-calcia-alumino silicate glass laser rod containing the following ingredients in approximate mole percentages:

The slurry was mixed for 10 minutes and poured into a gold crucible. The crucible was placed in an air circulating oven with the temperature maintained at 1 10 C. overnight to remove the water. The crucible was then placed in an electric resistance furnace with the temperature at 750 C. for 3 hours, or until homogenous, after which the molten glass immediately poured into a preheated (260 C.) graphite mold forming a disc having an 11/16 inch diameter and V4 inch thickness. The graphite mold was placed in an annealing oven maintained at 340 C. After 1 hour, at 340 C., the temperature of the annealing oven was lowered at a rate of 38 C. per hour to 250 C. after which the annealing oven was turned off and the mold cooled to room temperature.

The solid, annealed glass disc was removed from the mold, wet ground and polished with close tolerance to a thickness of 0.195 inches and a diameter of 0.687 inches. The refractive index of the finished polished glass disc was measured to be 2.14.

PART B The polished glass disc from Part A was tested for fluorescence intensity and decay time in a high power pulsed test system. The disc was placed in a holder and exposed to a beam of light from an E6 & G model FX 12-25 xenon flash lamp. The flash lamp had a flash duration of about 20 microseconds. The disc was not observed to solarize after repeated excitation by the flash lamp. The fluorescence intensity and decay time of the excited sample was measured by photographing the oscilloscope display of the 1060 nanometer fluorescent intensity versus time on a Tektronix Model 556, Dual Trace oscilloscope connected to an RCA S-l photomultiplier, having a narrow band pass filter.

The fluorescence intensity measurement was normalized against ED-2, a glass laser composition of Owenslllinois, Inc., comprising, in mole percent, 60.0 percent SiO 2.5 percent A1 0 27.5 percent Li O, 10 percent CaO, 0.16 percent Ce0 and 0.5 percent Nd O dis- 6 closed in U.S. Pat. No. 3,471,409, as Example 1. The 1.46. The fluorescence decay time was 156 microsecfluorescence intensity was found to be 3.40 when noronds. malized against the glass laser composition; 3.40 times the intensity of the glass laser composition. EXAMPLE 4 The fluorescence intensity was corrected for the re- 5 PART A fractive indices of the glass disc and the reference glass laser composition y A gram melt was prepared and polished glass discs prepared therefrom as described in Part A of Example F (corrected) F] (normalized) [(156)2/(n glass 1, except the molar or weight percentages of the raw di y] l0 materials were as follows:

Ingredients Mole Percent Weight Percent Host Glass Laser Article Host Glass Laser Article TeO, 65.0 64.6 81.7 80.2 ZnO 25.0 24.8 16.6 15.7 10.0 9.9 2.3 2.3 0.7 1.8

The corrected fluorescence intensity was 1.76. The flu- The refractive index of the finished polished glass disc orescence decay time was 150 microseconds. was measured to be 2.02.

EXAMPLE 2 PART B A .7. .7. WHEN. 7A..

A 15 gram melt was prepared and polished glass discs 1 The polished glass disc from Part A was tested for fluprepared therefrom as described in Part A of Example orescence intensity and decay time as described in Part 1, except the molar or weight percentages of the raw B of Example 1. The normalized fluorescence intensity materials-we ;7 n9$ 3 stewe vsrs ssn nt ns w Ingredients Mole Percent Weight Percent Host Glass Laser Article Host Glass Laser Anicle TeO, 75.0 74.6 88.8 87.4 ZnO 15.0 14.8 9.0 8.8 up 10.0 9.9 2.2 2.1 Nd O: 0.7 1.7

The refractive index of the finished polished glass disc 1.61. The fluorescence decay time was 165 microsecwas measured to be 2.06. onds.

PART B Other specific glass laser compositions set forth The glass dlsc from 3 A was E f herein as being suitable for use in the present invention orescence intensity and decay time as described in Part can be Substituted for the particular glass laser compo B of Example 1. The normalized fluorescence intensity Sitions used in the working examples to provide was and the corrected fluwescence mtenlty was stantially equivalent results. For instance, any of the The fluorescence decay time was 160 compositions set forth within the area formed by the onds' heavy lines connecting the points ABCDEF of the ter- EX 3 nary diagram can be used in place of the specific laser glass compositions used in the working examples to PART A provide an increased efficiency of at least about per- A 15 gram melt was prepared and polished glass discs cent when compared to the glass compositions of the prepared therefrom as described in Part A of Example 50 Redman patent and at least about 50 percent or more 1, except the molar or weight percentages of the raw when compared to the working examples of the Redmaterials were as follows: man patent.

Ingredients Mole Percent Weight Percent Host Glass Laser Article Host Glass Laser Article TeO 70.0 69.6 86.1 83.8 ZnO 20.0 19.8 11.8 12.2 Li,O 10.0 9.9 2.1 2.2 Nd o 0.7 1.8

. as. 2.. m .2. H-.. The refractive index of the finished polished glass disc wh i l i d i was measured to be 2.04. 1. A laser glass composition comprising TeO Li O and ZnO in which the proportions of TeO U 0 and PART B ZnO in molar amounts are defined by the area within The polished glass disc from Part A was tested for fluthe heavy lines connecting the points A, B, C, D, E, F orescence intensity and decay time as described in Part of the ternary diagram of the FIGURE of the drawings, B of Example 1. The normalized fluorescence intensity the laser glass composition including an effective lasing was 2.57 and the corrected fluorescence intensity was amount of 2 a- 2. A laser glass composition as defined in claim 1 in which the proportions of TeO Li O and ZnO are defined by the area within the heavy lines connecting points G, H, l, J, K, L in the ternary diagram of the FIG- URE of the drawings.

3. A laser glass composition comprising:

1. a host glass containing about 60-85 mole percent TeO about 2-20 mole percent Li O, and about 5-35 mole percent ZnO; and

2. an effective lasing amount of Nd O 4. A laser glass host composition comprising about 79-81 mole percent TeO about 4-6 mole percent U 0, and about 14-16 mole percent ZnO, the host composition containing about 0.01-l.5 mole percent Nd O 5. A laser glass composition as defined in claim 3 in which the host glass comprises about 80 mole percent TeO about 6 mole percent U 0, and about 14 mole percent ZnO.

6. A laser glass composition as defined in claim 3 in which the glass host comprises about 81 mole percent TeO about 5 mole percent Li- O, and 14 mole percent ZnO.

7. A laser glass composition as defined in claim 3 in which the glass host comprises about 79 mole percent TeO about 6 mole percent U 0, and about l5 mole percent ZnO.

8. A method for making a glass laser article such as a rod, disc, and the like, the method comprising the steps of:

l. melting laser glass batch-forming materials to provide a molten glass comprising TeO U 0 and ZnO in which the proportions thereof in molar amounts are defined by the area within the heavy lines connecting points A, B, C, D, E, F of the ternary diagram of the FIGURE of the drawings, and an effective lasing amount of Nd O 2. forming a glass blank from the molten glass; and

3. fabricating a laser article from the glass blank, the

article having increased lasing efficiency.

9. A method as defined in claim 8 in which the glass comprising TeO Li,0 and ZnO has amounts of TeO Li O and ZnO that are defined by the area within the lines connecting the points G, H, l, J, K, L of the ternary diagram of the FIGURE of the drawings.

10. The new use for a glass composition as a glass laser article in which the glass comprises TeO U 0 and ZnO in which the proportions thereof in molar amounts are defined within the area A, B, C, D, E, F formed by the heavy lines of the ternary diagram in the FIGURE of the drawings, and which glass composition is a host for an effective lasing amount of Nd O the new use comprising the steps of:

l. forming a glass laser article from the glass composition;

2. pumping the laser article to provide an energy inversion; and

3. lasing the pumped laser article.

11. A glass article made from the composition defined in claim 1.

12. A glass laser article made from the composition defined in claim 1, in the form of a rod.

13. A glass laser article made from the composition defined in claim 1, in the form of a disc.

14. A glass laser article made according to the method defined in claim 8. 

2. A laser glass composition as defined in claim 1 in which the proportions of TeO2, Li2O and ZnO are defined by the area within the heavy lines connecting points G, H, I, J, K, L in the ternary diagram of the FIGURE of the drawings.
 2. an effective lasing amount of Nd2O3.
 2. forming a glass blank from the molten glass; and
 2. pumping the laser article to provide an energy inversion; and
 3. fabricating a laser article from the glass blank, the article having increased lasing efficiency.
 3. lasing the pumped laser article.
 3. A laser glass composition comprising:
 4. A laser glass host composition comprising about 79-81 mole percent TeO2, about 4-6 mole percent Li2O, and about 14-16 mole percent ZnO, the host composition containing about 0.01-1.5 mole percent Nd2O3.
 5. A laser glass composition as defined in claim 3 in whicH the host glass comprises about 80 mole percent TeO2, about 6 mole percent Li2O, and about 14 mole percent ZnO.
 6. A laser glass composition as defined in claim 3 in which the glass host comprises about 81 mole percent TeO2, about 5 mole percent Li2O, and 14 mole percent ZnO.
 7. A laser glass composition as defined in claim 3 in which the glass host comprises about 79 mole percent TeO2, about 6 mole percent Li2O, and about 15 mole percent ZnO.
 8. A method for making a glass laser article such as a rod, disc, and the like, the method comprising the steps of:
 9. A method as defined in claim 8 in which the glass comprising TeO2, Li2O and ZnO has amounts of TeO2, Li2O and ZnO that are defined by the area within the lines connecting the points G, H, I, J, K, L of the ternary diagram of the FIGURE of the drawings.
 10. The new use for a glass composition as a glass laser article in which the glass comprises TeO2, Li2O and ZnO in which the proportions thereof in molar amounts are defined within the area A, B, C, D, E, F formed by the heavy lines of the ternary diagram in the FIGURE of the drawings, and which glass composition is a host for an effective lasing amount of Nd2O3, the new use comprising the steps of:
 11. A glass article made from the composition defined in claim
 12. A glass laser article made from the composition defined in claim 1, in the form of a rod.
 13. A glass laser article made from the composition defined in claim 1, in the form of a disc.
 14. A glass laser article made according to the method defined in claim
 8. 